scholarly journals Energy Retention in Thin Graphite Targets after Energetic Ion Impact

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6289
Author(s):  
Damjan Iveković ◽  
Petar Žugec ◽  
Marko Karlušić
Keyword(s):  
Ion Irradiation ◽  
High Energy ◽  
Energetic Ions ◽  
Track Formation ◽  
Geant4 Code ◽  
Energy Retention ◽  
Deposited Energy ◽  
Ion Impact ◽  
New Applications ◽  
The Impact

High energy ion irradiation is an important tool for nanoscale modification of materials. In the case of thin targets and 2D materials, which these energetic ions can pierce through, nanoscale modifications such as production of nanopores can open up pathways for new applications. However, materials modifications can be hindered because of subsequent energy release via electron emission. In this work, we follow energy dissipation after the impact of an energetic ion in thin graphite target using Geant4 code. Presented results show that significant amount of energy can be released from the target. Especially for thin targets and highest ion energies, almost 40% of deposited energy has been released. Therefore, retention of deposited energy can be significantly altered and this can profoundly affect ion track formation in thin targets. This finding could also have broader implications for radiation hardness of other nanomaterials such as nanowires and nanoparticles.

scholarly journals Ion tracks in silicon formed by much lower energy deposition than the track formation threshold

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
H. Amekura ◽  
M. Toulemonde ◽  
K. Narumi ◽  
R. Li ◽  
A. Chiba ◽  
...  
Keyword(s):  
Nuclear Energy ◽  
Energy Deposition ◽  
Ion Irradiation ◽  
High Energy ◽  
Electronic Energy ◽  
Synergy Effect ◽  
Ion Tracks ◽  
Track Formation ◽  
Low Energies ◽  
High Energy Ions

AbstractDamaged regions of cylindrical shapes called ion tracks, typically in nano-meters wide and tens micro-meters long, are formed along the ion trajectories in many insulators, when high energy ions in the electronic stopping regime are injected. In most cases, the ion tracks were assumed as consequences of dense electronic energy deposition from the high energy ions, except some cases where the synergy effect with the nuclear energy deposition plays an important role. In crystalline Si (c-Si), no tracks have been observed with any monomer ions up to GeV. Tracks are formed in c-Si under 40 MeV fullerene (C60) cluster ion irradiation, which provides much higher energy deposition than monomer ions. The track diameter decreases with decreasing the ion energy until they disappear at an extrapolated value of ~ 17 MeV. However, here we report the track formation of 10 nm in diameter under C60 ion irradiation of 6 MeV, i.e., much lower than the extrapolated threshold. The diameters of 10 nm were comparable to those under 40 MeV C60 irradiation. Furthermore, the tracks formed by 6 MeV C60 irradiation consisted of damaged crystalline, while those formed by 40 MeV C60 irradiation were amorphous. The track formation was observed down to 1 MeV and probably lower with decreasing the track diameters. The track lengths were much shorter than those expected from the drop of Se below the threshold. These track formations at such low energies cannot be explained by the conventional purely electronic energy deposition mechanism, indicating another origin, e.g., the synergy effect between the electronic and nuclear energy depositions, or dual transitions of transient melting and boiling.

THE USE OF MARKERS AND NUCLEAR MICROANALYSIS TO MONITOR ATOMIC TRANSPORT INDUCED BY ION BOMBARDMENT IN SOLIDS

1995 ◽  
Vol 09 (03n04) ◽  
pp. 163-186 ◽  
Author(s):  
LIONEL THOMÉ ◽  
FRÉDÉRICO GARRIDO
Keyword(s):  
Ion Irradiation ◽  
Ion Beam ◽  
Ion Bombardment ◽  
High Energy ◽  
Near Surface ◽  
Energetic Ions ◽  
Nuclear Microanalysis ◽  
Atomic Transport ◽  
Very High Energy ◽  
Marker Profile

This paper describes an original methodology developed to study the atomic transport in a solid target bombarded with energetic ions. This methodology is based on the use of heavy marker atoms introduced in the near-surface layer of the investigated target and the analysis via nuclear microanalysis techniques of the modifications of the marker profile due to ion bombardment. Results obtained in the case of low- or medium-energy (<10 keV/u ) ion irradiation, leading to the well-known ion-beam-mixing process induced by nuclear elastic collisions, are reported in the first part. The second part deals with the less-investigated case of very-high-energy (>1 MeV/u ) ion irradiation, where a dramatic plastic deformation mechanism induced by electronic excitation has been recently discovered.

The impact of high energy ion irradiation upon CO gas sensitivity of nanostructured GaN epilayers

2010 ◽  
Vol 46 (6) ◽  
pp. 535-537
Author(s):  
O. S. Volciuc ◽  
V. Popa ◽  
I. M. Tiginyanu ◽  
V. A. Skuratov ◽  
M. Cho ◽  
...  
Keyword(s):  
Ion Irradiation ◽  
High Energy ◽  
Gas Sensitivity ◽  
The Impact ◽  
Co Gas

Nanostructuring Rh(110) Surfaces by Ion Etching

2006 ◽  
Vol 960 ◽  
Author(s):  
Alessandro Molle ◽  
Andrea Toma ◽  
Corrado Boragno ◽  
Ugo Valbusa ◽  
Francesco Buatier de Mongeot
Keyword(s):  
Ion Irradiation ◽  
Incidence Angle ◽  
Chemical Reactivity ◽  
Hot Spot ◽  
Diffusion Mechanism ◽  
Surface Layers ◽  
Ion Impact ◽  
Impact Energies ◽  
The Impact ◽  
Very High

ABSTRACTThe ion irradiation of the Rh(110) surface results in the self-organised formation of various nano-structured morphologies like ripples, mounds, pyramids which have been thoroughly studied as a function of the incidence angle and of the impact energy of the impinging ions. A study of the evolution of the surface ripples at various impact energies above the hot-spot threshold, has been rationalized in terms of a contribution due to an ion-induced surface diffusion mechanism. In the very low ion incidence regime, where the formation of hot spots following ion impact is inhibited, the formation of a rhomboidal pyramid pattern is singled out and attributed to the predominant reorganization of surface adatom and vacancies produced in the topmost surface layers. The metastable rhomboidal pyramid pattern, was recently proven to have extraordinary chemical reactivity since it is endowed with a very high density of undercoordinated step sites runnin along the very open <1-12> azimuthal direction.

A Thermal Spike Model of the Amorphization of Insulators by High-Energy Heavy-Ion Irradiation

1994 ◽  
Vol 373 ◽  
Author(s):  
G. Szenes
Keyword(s):  
Ion Irradiation ◽  
Threshold Value ◽  
Heavy Ion ◽  
High Energy ◽  
Quantitative Relation ◽  
Thermal Spike ◽  
Thermal Spike Model ◽  
Spike Model ◽  
Track Formation ◽  
Basic Features

AbstractA model based on the assumption of a Gaussian temperature distribution in the thermal spike well accounts for the basic features of latent track formation. In good agreement with the observations it predicts a logarithmic variation of the track size for 2.7≥Se/Set≥1 and a linear variation for Se/Set≥2.7, where Se is the electronic stopping power and Set is a threshold value. The model also provides a quantitative relation between Set and the thermal properties of the target. A weak temperature dependence of track formation is predicted in agreement with the experiments.

Ion Tracks in Metals and Intermetallic Compounds

MRS Bulletin ◽  
1995 ◽  
Vol 20 (12) ◽  
pp. 29-34 ◽  
Author(s):  
A. Barbu ◽  
H. Dammak ◽  
A. Dunlop ◽  
D. Lesueur
Keyword(s):  
Energy Loss ◽  
Energy Range ◽  
Energy Deposition ◽  
Heavy Ion ◽  
High Energy ◽  
Electronic Energy ◽  
Nuclear Collisions ◽  
Surfaces And Interfaces ◽  
Track Formation ◽  
Deposited Energy

When an energetic ion penetrates a target, it loses its energy via two nearly independent processes: (1) elastic collisions with the nuclei (nuclear-energy loss (dE/dx)n), which dominate the ion slowing down in the low energy range (i.e., in the stopping region); (2) electronic excitation and ionization (electronic-energy loss (dE/dx)e), which strongly overwhelm (dE/dx)n in the high energy range (typically above 1 MeV/nucleon). Until the 1980s, researchers considered that electronic-energy deposition could participate in damaging creation in many insulators, but the effects observed in bulk metals were solely ascribed to elastic nuclear collisions. This widely held opinion was due to the fact that in metallic systems the numerous very mobile conduction electrons allow a fast spreading of the deposited energy and an efficient screening of the space charge created in the projectile wake so that it seemed unreasonable to hope for damage creation or track formation in metallic targets following high levels of electronic-energy deposition.A particular case is the observation more than 30 years ago of damage in thin or discontinuous. metallic films after fission fragment irradiation or MeV heavy ion bombardment. The spreading of the deposited energy is then strongly limited by the close vicinity of surfaces and interfaces.

Electron and ion irradiation-induced dissolution of mechanical twins in the intermetalic U3Si: An in situ HVEM study

1989 ◽  
Vol 47 ◽  
pp. 652-653
Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher
Keyword(s):  
Elevated Temperatures ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
High Energy ◽  
Mechanical Twinning ◽  
In Situ Experiments

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.

Transmission Electron Microscopy characterization of epitaxial III-V semiconductor thin films grown on Si(100) by ion-assisted deposition

1990 ◽  
Vol 48 (4) ◽  
pp. 686-687
Author(s):  
L. Hultman ◽  
C.-H. Choi ◽  
R. Kaspi ◽  
R. Ai ◽  
S.A. Barnett
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Irradiation ◽  
High Energy ◽  
Nucleation Mechanism ◽  
Layer By Layer ◽  
Extended Defect ◽  
Island Formation ◽  
Si Substrates ◽  
Transmission Electron

III-V semiconductor films nucleate by the Stranski-Krastanov (SK) mechanism on Si substrates. Many of the extended defects present in the films are believed to result from the island formation and coalescence stage of SK growth. We have recently shown that low (-30 eV) energy, high flux (4 ions per deposited atom), Ar ion irradiation during nucleation of III-V semiconductors on Si substrates prolongs the 1ayer-by-layer stage of SK nucleation, leading to a decrease in extended defect densities. Furthermore, the epitaxial temperature was reduced by >100°C due to ion irradiation. The effect of ion bombardment on the nucleation mechanism was explained as being due to ion-induced dissociation of three-dimensional islands and ion-enhanced surface diffusion.For the case of InAs grown at 380°C on Si(100) (11% lattice mismatch), where island formation is expected after ≤ 1 monolayer (ML) during molecular beam epitaxy (MBE), in-situ reflection high-energy electron diffraction (RHEED) showed that 28 eV Ar ion irradiation prolonged the layer-by-layer stage of SK nucleation up to 10 ML. Otherion energies maintained layer-by-layer growth to lesser thicknesses. The ion-induced change in nucleation mechanism resulted in smoother surfaces and improved the crystalline perfection of thicker films as shown by transmission electron microscopy and X-ray rocking curve studies.

scholarly journals Shock interactions in inviscid air and $$\hbox {CO}_2$$–$$\hbox {N}_2$$ flows in thermochemical non-equilibrium

Shock Waves ◽  
2021 ◽  
Author(s):  
C. Garbacz ◽  
W. T. Maier ◽  
J. B. Scoggins ◽  
T. D. Economon ◽  
T. Magin ◽  
...  
Keyword(s):  
Chemical Species ◽  
High Energy ◽  
Ideal Gas ◽  
Shock Interaction ◽  
Interaction Patterns ◽  
Shock Interactions ◽  
Wave Interference ◽  
Type V ◽  
The Impact ◽  
Non Equilibrium

AbstractThe present study aims at providing insights into shock wave interference patterns in gas flows when a mixture different than air is considered. High-energy non-equilibrium flows of air and $$\hbox {CO}_2$$ CO 2 –$$\hbox {N}_2$$ N 2 over a double-wedge geometry are studied numerically. The impact of freestream temperature on the non-equilibrium shock interaction patterns is investigated by simulating two different sets of freestream conditions. To this purpose, the SU2 solver has been extended to account for the conservation of chemical species as well as multiple energies and coupled to the Mutation++ library (Multicomponent Thermodynamic And Transport properties for IONized gases in C++) that provides all the necessary thermochemical properties of the mixture and chemical species. An analysis of the shock interference patterns is presented with respect to the existing taxonomy of interactions. A comparison between calorically perfect ideal gas and non-equilibrium simulations confirms that non-equilibrium effects greatly influence the shock interaction patterns. When thermochemical relaxation is considered, a type VI interaction is obtained for the $$\hbox {CO}_2$$ CO 2 -dominated flow, for both freestream temperatures of 300 K and 1000 K; for air, a type V six-shock interaction and a type VI interaction are obtained, respectively. We conclude that the increase in freestream temperature has a large impact on the shock interaction pattern of the air flow, whereas for the $$\hbox {CO}_2$$ CO 2 –$$\hbox {N}_2$$ N 2 flow the pattern does not change.

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